All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > General
Arrange The Disks (Posted on 2006-07-04) Difficulty: 4 of 5
A set of 47 disks are consecutively numbered 1 to 47 and placed in a row as follows: 1, 2, 3, 4, ... 45, 46, 47.

Rearrange the disks so for any two given disks A and B, the disk equal to their arithmetic mean doesn't lie between them. For example, Disk 4 cannot lie between Disk 1 and Disk 7 since the arithmetic mean of 1 and 7 is 4. However, since 7 is not equal to the arithmetic mean of 1 and 4, Disk 7 may lie between Disk 1 and Disk 4.

See The Solution Submitted by K Sengupta    
Rating: 3.6667 (3 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re: solution | Comment 2 of 14 |
(In reply to solution by Daniel)

But 5 is between 1 and 9; 8 is between 12 and 4. There are many others.  Here's the set of 115:

                     43  23  3           18  26  34
 1  5  9             39  35  31          18  30  42
 1  9  17            39  31  23          22  26  30
 1  13  25           39  27  15          22  30  38
 1  17  33           39  23  7           22  34  46
 1  21  41           35  31  27          26  30  34
 5  9  13            35  27  19          26  34  42
 5  13  21           35  23  11          30  34  38
 5  17  29           35  19  3           30  38  46
 5  21  37           31  27  23          34  38  42
 5  25  45           31  23  15          38  42  46
 9  13  17           31  19  7           44  40  36
 9  17  25           27  23  19          44  36  28
 9  21  33           27  19  11          44  32  20
 9  25  41           27  15  3           44  28  12
 13  17  21          23  19  15          44  24  4
 13  21  29          23  15  7           40  36  32
 13  25  37          19  15  11          40  32  24
 13  29  45          19  11  3           40  28  16
 17  21  25          15  11  7           40  24  8
 17  25  33          11  7  3            36  32  28
 17  29  41          2  6  10            36  28  20
 21  25  29          2  10  18           36  24  12
 21  29  37          2  14  26           36  20  4
 21  33  45          2  18  34           32  28  24
 25  29  33          2  22  42           32  24  16
 25  33  41          6  10  14           32  20  8
 29  33  37          6  14  22           28  24  20
 29  37  45          6  18  30           28  20  12
 33  37  41          6  22  38           28  16  4
 37  41  45          6  26  46           24  20  16
 47  43  39          10  14  18          24  16  8
 47  39  31          10  18  26          20  16  12
 47  35  23          10  22  34          20  12  4
 47  31  15          10  26  42          16  12  8
 47  27  7           14  18  22          12  8  4
 43  39  35          14  22  30
 43  35  27          14  26  38
 43  31  19          14  30  46
 43  27  11          18  22  26

  Posted by Charlie on 2006-07-04 13:43:37
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (2)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information